The fabrication of modern circuits typically involves several steps. Integrated circuits are first fabricated on a semiconductor wafer, which contains multiple duplicated semiconductor chips, each comprising integrated circuits. The semiconductor chips are then sawed (or diced) from the wafer and packaged. The packaging processes have two main purposes: to protect delicate semiconductor chips, and to connect interior integrated circuits to exterior connections.
In packaging integrated circuit (IC) dies (or chips), solder joining is one of the commonly used methods for bonding IC dies to package substrates, which may or may not include integrated circuits and/or other passive components. The packaged substrates may also include through silicon vias (TSVs). There are many challenges in IC packaging.